The present invention relates generally to a constant velocity joint and hub/bearing unit assembly. More specifically, it relates to a constant velocity joint and a hub/bearing unit that are attached and detached by a novel device.
A typical constant velocity joint 110, such as shown in FIG. 1, has a spindle 112 projecting through a hub 114. In this configuration, external access to the constant velocity joint 110 is provided for clamping the joint 110 to the hub 114 by tightening a nut 116 on an end of the spindle 112. To separate the joint 110 from the hub 114, the nut 116 is removed and force applied to the spindle 112 to remove it from the hub 114. These designs fail to meet current demands for lighter, less expensive constant velocity joint and hub units.
Modern designs, such as that disclosed in U.S. Pat. No. 6,203,441, have attempted to meet these demands. An embodiment of the U.S. Pat. No. 6,203,441 patent is shown in FIG. 2. The embodiment comprises a hub 120, a constant velocity joint 122 and an intermediate ring 124. The intermediate ring 124 is splined to the hub 120, and the constant velocity joint 122 is splined to the intermediate ring 124. The constant velocity joint 122 is attached to the intermediate ring 124 by a bistable elastic element 126 moveable between a first position A and second position B. In the first position, hooking members 128 of the element 126 attach the ring 124 to the joint 122. In the second position B, the hooks 128 no longer attach the joint 122 to the ring 124, and the joint 122 may be removed. However, it is difficult to remove the rotational backlash in the splined connection between the constant velocity joint 122 and the intermediate ring 124 without making assembly and disassembly very difficult. Furthermore, if the splines become corroded it will be difficult to remove the constant velocity joint 122 from the intermediate ring.
Other attempts have been made in the past to overcome the shortcomings of the prior art. For example, U.S. Pat. No. 3,586,357, in FIG. 2 of that patent, discloses a system whereby a central screw 84 is press-fitted into a bowl 85 of a transmission joint and facial teeth 87 are used to prevent rotation of the screw. A nut 86 is used to attach the screw to a hub. However, this varies from the prior art only slightly, as a screw pressed into a constant velocity joint varies only slightly from a constant velocity joint with an integrally formed spindle. The disclosure of the ""357 also requires the use of a very long screw in order to maintain proper tension on the threads of the nut and bolt to prevent the nut from coming loose. The long screw does provide extra weight and axial width, making the system of the ""357 patent unacceptable.
U.S. Pat. No. 6,146,022 discloses a constant velocity joint attached to a hub/bearing unit. However, the constant velocity of ""022 patent may not be removed from assembly without disassembling the hub/bearing unit. As a result, the assembly of the ""022 patent is inferior to the present invention because the constant velocity joint is not separately serviceable from the hub/bearing unit. In constant velocity joints, the weak link is the boot that maintains lubrication within the constant velocity joint and protects the constant velocity joint from contamination. If a boot fails, the constant velocity joint fails. In the case of the ""022 patent, the whole bearing assembly, or at least the inboard inner race, must be replaced in addition to the constant velocity joint.
In a first aspect, the present invention comprises an assembly comprising a hub/bearing unit, a constant velocity joint and an attachment device. The hub/bearing unit comprises a housing and a hub. The hub comprises a centrally located bore and a flange having an inboard surface. The hub/bearing unit further comprises a plurality of rolling elements between the housing and the hub that rotatingly support the hub within the housing. The constant velocity joint comprises an inner joint, an outer joint member disposed about the inner joint member, and a plurality of balls between the inner joint member and the outer joint member. The balls transmit rotational force between the inner joint member and the outer joint member. The attachment device has a threaded portion and a shoulder portion, wherein the shoulder portion contacts a backing surface of the constant velocity joint to attach the constant velocity joint to the hub/bearing unit. The attachment device does not extend beyond a plane defined by the inboard surface of the flange when the attachment device is installed within the assembly.
In a second aspect, the present invention comprises a device for attaching a constant velocity joint comprising an outer joint member having a backing surface on an internal surface thereof to a hub/bearing unit comprising a hub with a centrally located threaded bore. The device comprises an attachment device with a threaded portion, a shoulder portion and an end portion. The threaded portion is adapted to be threaded into the centrally located threaded bore to, in cooperation with the shoulder portion, maintain the attachment device in a fixed relationship with the constant velocity joint and the hub/bearing unit. The shoulder portion is adapted to abut a backing surface of the outer joint member to hold the outer joint member in a fixed relationship with the hub/bearing unit. The end portion is adapted to contact the constant velocity joint to force separation of the constant velocity joint from the hub when an axial force is applied thereto.
In a third aspect, the present invention provides a method of separating a constant velocity joint from a hub/bearing unit comprising four steps: a) providing a hub/bearing unit, b) providing a constant velocity joint, c) providing an attachment device for attaching the constant velocity joint to the hub/bearing unit, the attachment device comprising a shoulder portion and a threaded portion, and d) clamping the constant velocity joint to the hub/bearing unit wherein the attachment device, constant velocity joint and hub/bearing unit are adapted to apply an axial force to the constant velocity joint to remove the constant velocity joint from the hub/bearing unit as the attachment device is disengaged from the hub/bearing unit.
In a fourth aspect, the present invention comprises an assembly comprising a hub/bearing unit, a constant velocity joint and an attachment device. The hub/bearing unit comprises a housing and a hub comprising a centrally located bore and a flange having an inboard surface. The hub/bearing unit further comprises a plurality of rolling elements between the housing and the hub that rotatingly support the hub within the housing. Finally, the hub/bearing unit comprises splines on an external diameter of the hub. The constant velocity joint comprises an inner joint, an outer joint member disposed about the inner joint member. A plurality of balls is disposed between the inner joint member and the outer joint member wherein the balls transmit rotational force between the inner joint member and the outer joint member. The constant velocity joint further comprises splines on an external diameter thereof that mesh with the internal splines of the hub/bearing unit. The attachment device comprises a threaded portion and a shoulder portion, wherein the shoulder portion contacts a backing surface of the constant velocity joint to clamp the constant velocity joint to the hub/bearing unit. The attachment device is adapted to exert an axial force to the constant velocity joint in order to remove the constant velocity joint from the hub/bearing unit.